Prognostic Meteorological Discussion
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022
FXAK02 KWNH 021937
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
336 PM EDT MON MAY 2 2016

VALID 12Z FRI MAY 06 2016 - 12Z TUE MAY 10 2016

THE BEGINNING OF THE FORECAST PERIOD EARLY FRIDAY MORNING WILL BE
FEATURED WITH A LARGE SCALE TROUGH AND CLOSED LOW JUST SOUTH OF
THE NORTHERN ALEUTIANS, AND RIDGING TO THE NORTHEAST ACROSS
INTERIOR ALASKA AND WESTERN CANADA.  THIS IS WELL AGREED UPON BY
THE GEFS MEAN, CMC MEAN, AND ECMWF MEAN SOLUTIONS.  RIDGING IS
ALSO EVIDENT OVER THE BERING SEA AND THE WESTERN ALEUTIANS.

GOING INTO THE DAY 5 AND 6 PERIOD OVER THE WEEKEND, THE MID-LEVEL
FLOW PATTERN TRANSITIONS INTO MORE OF A ZONAL FLOW COMPARED TO THE
HIGHER AMPLITUDE PATTERN ON FRIDAY.  IT IS THIS TRANSITION THAT
ALLOWS GREATER MODEL DIFFERENCES TO EMERGE, ESPECIALLY BY THE DAY
7 PERIOD WHEN A BLEND OF THE NAEFS/EC MEAN WAS USED WITH NO
DETERMINISTIC GUIDANCE.  DIFFERENCES WELL UPSTREAM OVER CENTRAL
RUSSIA HAVE MUCH TO DO WITH THE EVOLVING MODEL SPREAD THAT WAS
NOTED.  BY THE END OF THE PERIOD, THERE IS DECENT MODEL AGREEMENT
WITH RESPECT TO A LARGE CLOSED LOW OVER THE BERING SEA, ALONG WITH
AN OCCLUDED SURFACE LOW.

IN TERMS OF SENSIBLE WEATHER, EXPECT SEASONABLY MILD CONDITIONS
SOUTH OF THE BROOKS RANGE, WHERE THE ARCTIC FRONTAL BOUNDARY IS
FORECAST TO BE AND SEPARATE MUCH COLDER TEMPERATURES AND
SUB-FREEZING TEMPERATURES CLOSE TO THE ARCTIC COAST.  WIDESPREAD
RAIN AND MOUNTAIN SNOW IS EXPECTED FROM SOUTHERN ALASKA TO THE
PANHANDLE REGION THROUGH SATURDAY, AFTER WHICH A DRIER PATTERN
BEGINS TO COMMENCE.

D. HAMRICK

$$





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